Leaning Tower of Pisa

The iconic Leaning Tower of Pisa is the freestanding bell tower of the city’s cathedral, well known for its lean of approximately 4 degrees. Prior to 1990, the tower actually leaned 5.5 degrees. The leaning is due to an unstable foundation that couldn’t account for the weight of the tower that was built over 177 years, starting in 1173. Controversy about the architect of the tower still exists today.